Not reading item.tag correctly

[jafix]

manager.on('newOffer', function (offer) {
var onlyCards = (offer.itemsToReceive.every(function(item) {
			return item.tag == "Trading card" && item.tag == "Not Marketable";
			}));
			
			console.log('[OFFER] Checking offer containments');
			if (onlyCards) {
				receiveCardAmount = offer.itemsToReceive.length
				giveCardAmount = offer.itemsToGive.length
				
				if (receiveCardAmount == 2) {
					console.log('[OFFER] Received items = 2');
					
					if (giveCardAmount == 1) {
						
						console.log('[OFFER] Given items = 1');
						
						offer.accept();
						client.chatMessage('76561198259000054', 'Trade offer #' + offer.id + ' from ' + offer.partner.getSteamID64() + ' accepted. 2 new cards in inventory');
						tradelog.info('Trade offer #' + offer.id + ' from ' + offer.partner.getSteamID64() + ' accepted. 2 new cards in inventory')
						console.log('[OFFER] Accepted - contains correct items');
					}
				}
				
			} else {
				offer.decline();
				console.log('[OFFER] Declined - contains non card items or not the correct amount');
				tradelog.info('Offer #' + offer.id + ': Declined - contains non card items')
				}
			}
		});
});

My offer gets declined even though I'm sure I matched everything. I think it's with the tags but it might be a problem with the item amount

[TomYoki]

1#

Tags are an array.

2#

Items in trade-offers don't have tags.